Support for TransactionAwareCacheDecorator

This commit makes sure to unwrap any transaction aware cache before
collecting metrics for them.

Closes gh-8984

Author: snicoll

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/CachePublicMetrics.java

@@ -27,7 +27,9 @@
 import org.springframework.boot.actuate.metrics.Metric;
 import org.springframework.cache.Cache;
 import org.springframework.cache.CacheManager;
+import org.springframework.cache.transaction.TransactionAwareCacheDecorator;
 import org.springframework.core.ResolvableType;
+import org.springframework.util.ClassUtils;
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
 
@@ -87,7 +89,7 @@ private void addMetrics(Collection<Metric<?>> metrics, String cacheName,
 			List<CacheManagerBean> cacheManagerBeans) {
 		for (CacheManagerBean cacheManagerBean : cacheManagerBeans) {
 			CacheManager cacheManager = cacheManagerBean.getCacheManager();
-			Cache cache = cacheManager.getCache(cacheName);
+			Cache cache = unwrapIfNecessary(cacheManager.getCache(cacheName));
 			CacheStatistics statistics = getCacheStatistics(cache, cacheManager);
 			if (statistics != null) {
 				String prefix = cacheName;
@@ -100,6 +102,14 @@ private void addMetrics(Collection<Metric<?>> metrics, String cacheName,
 		}
 	}
 
+	private Cache unwrapIfNecessary(Cache cache) {
+		if (ClassUtils.isPresent("org.springframework.cache.transaction.TransactionAwareCacheDecorator",
+				getClass().getClassLoader())) {
+			return TransactionAwareCacheDecoratorHandler.unwrapIfNecessary(cache);
+		}
+		return cache;
+	}
+
 	@SuppressWarnings({ "rawtypes", "unchecked" })
 	private CacheStatistics getCacheStatistics(Cache cache, CacheManager cacheManager) {
 		if (this.statisticsProviders != null) {
@@ -140,4 +150,19 @@ public CacheManager getCacheManager() {
 
 	}
 
+	private static class TransactionAwareCacheDecoratorHandler {
+
+		private static Cache unwrapIfNecessary(Cache cache) {
+			try {
+				if (cache instanceof TransactionAwareCacheDecorator) {
+					return ((TransactionAwareCacheDecorator) cache).getTargetCache();
+				}
+			}
+			catch (NoClassDefFoundError ex) {
+				// Ignore
+			}
+			return cache;
+		}
+	}
+
 }

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/endpoint/CachePublicMetricsTests.java

@@ -18,6 +18,7 @@
 
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -29,7 +30,10 @@
 import org.springframework.boot.actuate.cache.ConcurrentMapCacheStatisticsProvider;
 import org.springframework.boot.actuate.metrics.Metric;
 import org.springframework.cache.CacheManager;
+import org.springframework.cache.concurrent.ConcurrentMapCache;
 import org.springframework.cache.concurrent.ConcurrentMapCacheManager;
+import org.springframework.cache.support.SimpleCacheManager;
+import org.springframework.cache.transaction.TransactionAwareCacheDecorator;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.entry;
@@ -78,6 +82,19 @@ public void cacheMetricsWithMultipleCacheManagers() {
 				entry("cache.anotherCacheManager_foo.size", 0L));
 	}
 
+	@Test
+	public void cacheMetricsWithTransactionAwareCacheDecorator() {
+		SimpleCacheManager cacheManager = new SimpleCacheManager();
+		cacheManager.setCaches(Collections.singletonList(
+				new TransactionAwareCacheDecorator(new ConcurrentMapCache("foo"))));
+		cacheManager.afterPropertiesSet();
+		this.cacheManagers.put("cacheManager", cacheManager);
+		CachePublicMetrics cpm = new CachePublicMetrics(this.cacheManagers,
+				providers(new ConcurrentMapCacheStatisticsProvider()));
+		Map<String, Number> metrics = metrics(cpm);
+		assertThat(metrics).containsOnly(entry("cache.foo.size", 0L));
+	}
+
 	private Map<String, Number> metrics(CachePublicMetrics cpm) {
 		Collection<Metric<?>> metrics = cpm.metrics();
 		assertThat(metrics).isNotNull();